Phonograph-record.



-UNITED STATES PATENT OFFICE.

JosIAH B. MILLET, oF EosToN, MASSACHUSETTS, AssIGNoE To BosToN TALKING MACHINE COMPANY, or EosToN, MAssAcHUsETTs, A coEPoRATIoN or MAINE.

rHoNoGaAPH-RECOED.

Specification of Letters Patent.

Patented Dee. una.

Application led January 5, 1911. Serial No. 600,902.

, graph-Records, of which the following dcscription, in connection with the accompanying drawings, is a specification, like letters on the drawings representing like parts.

This invention relates to phonographrecords and more particularly though not exclusively to records in disk form.

. The invention will be best understood by reference to the following description when taken in connection with the accompanying illustration of one or more specific embodiments thereof, while its scope will be more particularly pointed out in the appended clalms.

In the drawings: Figure l shows the component parts of a disk record embodying'one form of my invent-ion in the condition in which such parts are prior to pressing; Fig. 2 shows the complete record after pressing; Fig. 3 shows in cross section a portion of composition sheet material from which a record made according. to one form of the invention may be formed; Fig. 4 shows a disk formed from such' material prior to pressing; Fig. 5 shows a' completed record after pressing; and Fig. 6 shows a modified form of record.

AReferring to the drawings and first to the embodiment of my invent-ion shown in Figs. l and 2, I have there illustrated one form of record consisting of a superior type of double-faced record disk having sound grooves of varying depth, that is to say, of the socalled hill and valley type.

In the production of double-faced record disks it has heretofore been the common practice to use a homogeneous body of plastic record material with the sound grooves on opposite faces pressed into onefand the' same mass of material. Such a doublefaced record disk is described in patent to Petit No. 7 49,092, where it is stated that the simultaneous pressure by the opposing matrices in the die under similar conditionsk and inone and the same homogeneous mass of plastic material insures uniformity inthe flow of the said material at both faces of the disk.

I have found that in the case of doublefaced records and especially those having Sound grooves with vertical undulations or of varying depth,the best results are ob tained by avoiding the use of a homogeneous or continuous mass of plastic material.

One feature of my invention consists in so dividing or separating the plastic material presented to one matrix from the plastic @material presented. to the other matrix that instead of securing a common uniform dis- I placement at both sides of the same undivided intermediate plastic mass under the action of the two opposing matrices, the displacement or flow of the one mass facing the one matrix takes place independently of the flow or displacement of thefseparated mass facing the opposite matrix.

The quality of -a sound recordis largely dependent upon the density anduniformity of the record material in and about thev record groove. In the case of records of the degree of thinness commerciallyv employed, if a single homogeneous mass of material is used the displacement of material under one matrix appears to interfere with or modify the free displacement of material under the opposing matrix, so that there tends to result a variation and inferiority inthe quality ofthe record which seems to be due to a variation in the density of the material under different port-ions of the ,sound groove.

This is caused,l as I apprehend, by the fact. that the varying and irregular projections on the face of one Amatrix acting on the thin homogeneous intermediate layer lof plastic material so modifies the movement of such material that the freedom and facility with which the material 'atthe bottom of the groove adapt-s itself -to such varying and irregular projections on the face of the opposing matrix is impaired. In other words, not-withstanding that a differential or nonuniform flow at opposite sides should be permitted, a uniformity of flow is enforced by this process, which flow is the resultant of the two displacements at the two opposite faces. This is the case with records having sound grooves provided with lateral undulations aswell as those having sound grooves provided with vertical uudulations,

although in the latter case the interference between the displacement of material at one side and the displacement of material at the opposite side seems more directly to impair separator acting as a partition between theA material presented to one matrix and the material presented to the other, and thereby interruptlng the continuity and homogeneity of the material will separate the plastic mass for purposesoffow andr displacement into two distinct bodies so. that, while the pressure of one matrix is transmitted from one mass through the separator to the other mass, and the said matrix is thereby effective in pressing the material into the irregular pro]ections of the o posing matrix in .just the same way -thatt e' smooth faced platenis effective in pressing a single faced record, nevertheless the displacement or -tlow of plastic materialunder and about the projections of such matrix is free and unimpaired and independent of the displacement or flow of the separated mass of material under and about the projections of said opposing matrix, and vice versa.

While the thickness of the separator. is in a sense quite immaterial so long as it does not amount to what might be termed a backing, it is preferable that it be made as thin as possible and form as small a part of the. mass of the record as is consistent with the,

separation of the two bodies of plastic material as regards independence of flow in the plastic state when in the press and under lthe action ofthe two matrices. Nor is it essential, though ordinarily preferable, that the separator consist of an impervious or im-. penetrable division wall, for a coarsely fabricated, porousor meshed material ,might suiice under suit-able conditions to separate the iow of plastic material on the two sides of the disk and allow one to take place independently of the other,

Any suitable material may be employed for the separator, but good results are obtained by using a sheet of paper, preferably thin, tough and smooth. The thickness need not exceed one one-hundredth of an inch, or less. Thin bond paper seven or eight thousandths of an inch thick will serve the purpose. v

I am awa-re that disk records have been made composed in part of pasteboard sheets or the like, but in such cases such material has been in the form of a backing or foundation body and.` the object has` been to stren hen the structure of the record by the additlon of a large mass of cellular material or to cheapen the cost of roduction by substitutin for the inner b y portion 0f the recor a relatively large amount of cheaper material for the more expensive plastic material. In such cases a large or the largest part of the mass of the record has been composed of the pastebo'ard orV other cellular material used and the plastic record receiving'material has been applied thereto in the form of a thin surface film.

The best results, however, in` the case of sound grooves having vertical undulations are only obtained where there is providedv a relatively large mass of the plastic recordreceiving material under the sound oove to -a'ct as -a body or foundation there or, such.'

foundation materiall `improving the tone and the resonantquaity of the record. fByV providing a thin vpaper or other separating wall between the two bodies of plastic mation or the record, but as a mere partition, the total mass of preciably or harm ully diminished and each record oove has substantially the requisite lastic material is not apterialf to serve, ynot as a backing or founda- Y underlying foundation or body of recordreceiving material to maintain the tone and quality of the record.

The resonant qualities of the 'disk may in fact be improved by a judicious yselection of the material of whlch the separator is com-v posed, while still leaving the major body of the disk composed of plastic record material. I have found thata thin layer of porous paper, such for example, as'thin blotting paper will act as a separator and at the same time improve the resonant qualities of the disk, or two very thin layers of wood glued together with the grain arranged at right angles to prevent splitting, will serve as a resonant separator. v

The separation of the record into' two parts by the thin separator not only improves a record and particularly one of the hill and valley ty e, for the reasons stated, whlle giving 1t al the tone quality which a solid homo eneous record possesses due tothe presence o a relatively large body of record material at and under the sound groove, but. Vthe separation of the record into distinct laminas or layers, apart from any structural strength residing 1n the separator itself, materially improves the structure o ,f the record by diminishingthe brittleness thereof and reducing the likelihood of breakage.

In forming a disk record in accordance with my invention any suitable plastic material may be employed, but ordinarilysuch material will comprise the customary and well known mixture of shellac and china clay or other infusorial earth or any suitbeing placed on top of the said lump and` then another lump of the plastic material upon the separator, the composite mass being thereupon subjected to the action of the press. Preferably, however, I previouslyils Ashape the plastic material by punching-or cutting so that it has the form of disks of uniform thickness, or ,the al proximate form of disks of uniform thickness. Such a disk is represented at a in Fig. 1 being perforated at b to receive the centering pm of the matrix. The parts in Figi. 1 as well asin the remaining figures'of the rawings are shown of exaggerated thickness for the sake of 'clearness Such disk referably has a thickness about or somew at greater than half the thickness of the finished record, for example about onethirty-secondl of an inch. This disk being placed upon the centering pin and upon the lower matrix, a centrally perforated disk c of thin paper is placed' upon it and on to of the: paper is then placed a second dislk o of plastic material similar to the disk a. This composite disk being then subjected to the action of the press, the upper and lower matrices will leave their imprints in opposing facesof the record, the separator c, however, preserving the required independence of flow or disV placement as between the separatemasses of plastic material on opposite sides thereof as has been more fully referred to above.

The completed reco-rd shown in Fig. 2 will comprise two solid layers of record material each of suiicient mass to give the re uisite tone quality, such layers, however, eing separated by the paper separator and being much less brittle than a solid record.

The paper disk c may be (3o-extensive with the disks a and a', or may bemuch smaller in diameter, while still maintaining the desired independence in iow. Preferably, however, while extending beyond the limits of the sound record groove the said paper disk has its diameter somewhat less than that of the disks a and a', so that the edges of the. said paper will be slightly 'embedded in or coated by the material of the finished record as represented in Fig. 2 and therefore invisible. This may not always be necessary as the compression ofthe mass of thejrecord will necessarily force the material over the edges ofl the paper.

If,` desired, a single composite disk provided with its separator may be previously. formed before the soundgroove or grooves are pressed into its faces, suchpreviously prepared diskconsisting of an upper and lower layer of plastic materialV with an intervening separator. This can be done by rolling out the material linto sheet form under heated rolls. kA. fragment of such material is represented in Fig. 3, this consisting nf a continuous lower layer of plastic material l of the required thickness, an upper layer e of substantially the same thickness and a relatively thin intervening paper sheet f. From such sheet material a perforated disk such as is shown in Fig. 4 can be punched 65 out,`and this being placed in the press may therefrom, forming the completed disk represented in Fig. 5.

In the usual process of pressing records where no separator is employed the free displacement and flow of the plastic material,

which is ordinarily heavily charged with clay or other gritty matter, results in excessive frictional wear upon the matrices, necessitating their fre uent renewal. The use of the separator, W ile leavingl the material free to conform to the contourof the ma-` receive the impression of the sound grooves trix, lessensthe total aggregate displacement i of the material toward the sides ofthe disk and saves a corresponding amount. of wear upon the matrix. The excessive flow of mal terial toward the sides of the disk moreover, and therefore the wear upon the matrix, is materially reduced by the previous prepaation of the plastic material in sheet and. disk form, or vapproximate disk form,`as de- I scribed, prior to the pressing action, the final pressing action being relied upon merely -to impress the record groove into the material and slightly compress the disk as incidental to its operation.

The subdivision of the disk into layers reduces the liability to breakage, and the thinness of the record may therefore be reduced.

and the amountof plastic material may bei cut down to the minimum amount which is required to give the desired tone` and resonant. quality. A

v The formation of the disk in the manner described permits the utilization at opposite.

-faces thereof of masses of record receiving material having distinctly different characteristics, but each best adapted to receive the imprint of the particular kind of sound groove intended to4 be impressed therein. For example, the disk a in Fig. 1 may be composed of shellac mixed with a large proportion of clay and have impressed therein a record groove of a brass band, while the opposite disk a may vbe composed'of shellacl charged with Celluloid or other ingredients intended to 'provide a smoother surface and more effective groove for ay soprano solo, violin or string quartet. This sub-division of the disk furthermore permits the em. lI

4ployment of separate and opposite masses of suitable pigments the material on one sideof the separator may be colored bluel and the material on the opposite side of the separator red, green, or some contrasting color other than blue. This makes it possible to distinguish at a glance which side of the disk is uppermost and when employed in connection with' a system of impressing one class of pieces, for example, band music, into material of one color', and' another class of pieces, for example, vocal music, into the material of another color, affords means for chara' ei' of surface.

readillyC identifying the recor `which is-uppermos'. --71 `In Fig.v 6 I have shown 'anotherflform-of 'disk record-Where a thiw paperpartition g is provided which serves to separate the rele atively thick mass h of plastic lmaterials which may have Athe same composition as in the case of the 'disk -a in Flg. 1, figo'm a second body of material z' whlchherein isv thinner than the la er la, and may consist ofcelluloid, or celluloidwithother ingredients such as shellac with a small proportion of crocus powder, intendedto give a, smoother surface sotha't that side of the 'disk may be ,iitted to receive record grooves of pieces re quirin for their best reproduction-suche. The Celluloid may be applied in -sheetform and ifI so, being of lesser plasticity than the materialh, the paper sheet g may then be omitted.

It will be obvious that my invention, while especially advantageous as to some of its features to double disk records, is not limited to disk records having sound grooves on both faces thereof nor alone to records provided with lglrooves having vertical undulations, but at as to certain of ,its features it is applicable to records having sound grooves provided with lateral undulations and to single record disks as well as to records having a cylindrical form.

While, for purposes of illustration, I have herein shown and described one specific form of my invention, it is to be understood that the same is not limited to the detailsv herein described, but these may be varied within wide limits Without departingv from the spirit thereof.

Claims 1. A molded sound record comprising fa sheet of paper and resinous thermo-plastic record-materialen either side of saidvpaper, the whole pressed into an adherent mass,

amasarthermo plastic record material bein l suilicientlyfthickto render the record rig-1 and resonant and the paper suiciently thin rtablier: to the irre ularities of theinterio!` sur-:timeof the lastic material. v

2. Ainiolde sound record comprising a thin `separating sheet-of flexible material and resinous thermo-plastic record material -on either side of saidseparating sheet, the whole the fibrous material suiliciently thin toiex Itothe irregularities of the interior surface of the plastic material.

4. A molded sound 'thin sheet of fibrous material and plastic rec- -ord materialen either sideof said fibrous 'material, the whole pressed while said record material is in a substantially uniform semi-fluid stateintoanadherent mass, the fplastic record material 1 being sutliciently Lthickto render Vthe retprdfrigidand' resorecord comprising a lnant, and: the brous j material 'sufficiently thin toQex to the irregularities of the interior surface of the plastic material.

Inv testimony. whereof, I 'haveesigned my name to this specification, in the presence .of two subscribing Witnesses. Y

p J OSIAH B. MILLET. Witnesses:

Evnnm'r; S.l Emmi', THOMAS -B. Boom. 

